From 7e640e4207d4c1260566e6074bf3d8d9c029e986 Mon Sep 17 00:00:00 2001
From: Maxim Dolgolyov <maxim.dolgolyov@gmail.com>
Date: Wed, 3 Jun 2026 20:23:27 +0300
Subject: [PATCH] =?UTF-8?q?fix(svg-draw):=20=D1=80=D0=B5=D0=B0=D0=BB=D1=8C?=
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Прошлый гард не работал: dragstart срабатывает на самой карточке (draggable=true), а не на
svg, поэтому e.target.closest(.svgdraw-host) был null. Теперь на pointerdown снимаем
draggable с ближайшего предка-карточки и возвращаем на pointerup — холст рисует, а не тащит блок.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 frontend/js/svg-draw.js | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/frontend/js/svg-draw.js b/frontend/js/svg-draw.js
index a79c810..5e23533 100644
--- a/frontend/js/svg-draw.js
+++ b/frontend/js/svg-draw.js
@@ -200,8 +200,23 @@
     /* ── drawing interaction ──────────────────────────────────────── */
     let drawing = false, startP = null, curEl = null, penPts = null, dragMode = null, dragStart = null, selStartXY = null;
 
+    /* The host lesson block-card is draggable=true and hijacks mouse-drag on the
+       canvas — and its dragstart fires on the CARD (not the svg), so it can't be
+       cancelled here. Fix: disable the nearest draggable ancestor while a pointer
+       is down on the canvas, restore on release. */
+    let _dragAnc = null;
+    function suppressAncestorDrag() {
+      const a = svg.closest && svg.closest('[draggable="true"]');
+      if (a) { _dragAnc = a; a.setAttribute('draggable', 'false'); }
+    }
+    function restoreAncestorDrag() {
+      if (_dragAnc) { _dragAnc.setAttribute('draggable', 'true'); _dragAnc = null; }
+    }
+    document.addEventListener('pointerup', restoreAncestorDrag);
+
     svg.addEventListener('pointerdown', function (evt) {
       if (evt.button !== 0) return;
+      suppressAncestorDrag();
       const p = svgPoint(evt);
 
       if (state.tool === 'select') {
@@ -274,6 +289,7 @@
     });
 
     function endDraw(evt) {
+      restoreAncestorDrag();
       if (dragMode === 'move') { dragMode = null; commit(); return; }
       if (!drawing) return;
       drawing = false;
@@ -466,6 +482,7 @@
 
     function destroy() {
       document.removeEventListener('keydown', onKey);
+      document.removeEventListener('pointerup', restoreAncestorDrag);
       if (root.parentNode) root.parentNode.removeChild(root);
     }